Subsurface valve having an energy absorption device

ABSTRACT

A system for completing a well bore, comprises, a string having a housing, a valve having a valve seat positioned within the housing, the valve seat having an inner channel, a flapper pivotally coupled to the valve seat in which the flapper is configured to move from a first open position to a second closed position such that the inner channel is at least partially obstructed. An energy dampening device is coupled to the valve seat, such that the energy dampening device is configured to at least partially absorb an impact of the flapper on the valve seat.

BACKGROUND

The present application relates generally to the field of tools for completing subterranean wells. In particular, the application relates to subsurface valves.

Hydrocarbon fluids such as oil and gas are found in subterranean portions of geological formations or reservoirs. Wells are drilled into these formations for extracting the hydrocarbon fluids. Completed wells are often equipped with one or more safety valves. The safety valve provides a failsafe in the event of a catastrophic event at the surface or along the well bore above the safety valve.

Safety valves are commonly flapper valves which open downwards. Pressure of the wellbore fluids bias the flapper towards the closed position. A sleeve inside the flapper valve keeps the valve open when the well is in operation. The sleeve may be maintaned in position by hydraulic pressure from the surface. Should the wellhead be lost or, in the case of a deep sea well, the fluid lines from the sea bed to the platform be compromised, the loss of hydraulic pressure against the sleeve would result in the sleeve sliding upwardly and the safety valve will close to prevent further flow of wellbore fluids out of the well.

Prior to producing hydrocarbon fluids, wells must often be completed by one or more of a variety of processes. The completion processes may include perforating the well casing and/or reservoir (i.e., by use of shape charges), fracturing the formation, applying chemical treatments to the formation, gravel packing the well, or other processes.

In many applications, a single well bore may pass through more than one reservoir. In these cases, it may be desirable to complete more than one well bore zone. Accordingly, a first production zone may be completed at a down hole location. Then a second production zone may be completed in a position above (i.e., closer to the surface) the first production zone. When carrying out the completion processes above the first production zone, completion fluids (i.e., gravel slurries, propants, acidifiers, and other completion fluids) from the second production zone may migrate down hole. Additionally, the addition of completion fluids in the well bore region proximate to the second production zone may pressurize the well bore and cause completion fluids from well bore region proximate to the second production zone to migrate to the well bore region proximate to the first production zone and ultimately into the first production zone of the formation. Also, the pressurization of the well bore may cause completion fluids remaining in the well bore region proximate to the first production zone to migrate into the first production zone of the formation.

The migration of undesired completion fluids into a production zone may damage the formation and reduce the productivity of the well. Accordingly, it may be desirable to isolate the first production zone from the second production zone during the time when the first production zone has been completed and the second production zone is undergoing completion processes. This isolation may be carried out by the use of a flapper valve.

In both the case of isolation and safety valves, the flapper valve may be damaged if it is closed too harshly. This is especially true for safety valves where a sudden loss of hydraulic pressure on the sleeve could result in the slamming or forceful impact of the flapper against a flapper seat. This may damage one or more of the valve components and result in a fluid losses. Accordingly, there is a need for a device to absorb the energy of a sudden valve closure to prevent or mitigate damage to the valve.

SUMMARY

One embodiment of the invention relates to a system for use in a wellbore. The system comprises a string having a housing, a valve having a valve seat positioned within the housing, the valve seat having an inner channel, a flapper pivotally coupled to the valve seat, the flapper configured to move from a first open position to a second closed position in which the inner channel is obstructed, and an optional sleeve positioned in the inner channel of the valve seat and configured to retain the flapper in the first open position. An energy dampening device is coupled to the valve seat, such that the energy dampening device is configured to at least partially absorb an impact of the flapper on the valve seat.

Another embodiment relates to a system for conveying wellbore fluids. The system comprises a string having a housing, a safety valve having a valve seat positioned within the housing, the valve seat having an inner channel, a flapper pivotally coupled to the valve seat, the flapper configured to move from a first open position to a second closed position in which the inner channel is obstructed, and an optional sleeve positioned in the inner channel of the valve seat and configured to retain the flapper in the first open position. An energy dampening device is coupled to the valve seat, and the energy dampening device is configured to at least partially absorb an impact of the flapper on the valve seat.

Yet another embodiment relates to a valve for use in a wellbore comprising a valve seat, the valve seat having an inner channel, a flapper pivotally coupled to the valve seat, the flapper configured to move from a first open position to a second closed position in which the inner channel is obstructed, and an optional sleeve positioned in the inner channel of the valve seat and configured to retain the flapper in the first open position. An energy dampening device is coupled to the valve seat and the energy dampening device is configured to at least partially absorb an impact of the flapper on the valve seat.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of wellbore system.

FIG. 2 is a cross-sectional view of a flapper valve.

FIG. 3 is a perspective view of a flapper valve.

FIG. 4 is another cross-sectional view of a flapper valve.

FIG. 5 is a cross-sectional view of the flapper valve.

FIG. 6 is another cross-sectional view of a flapper valve.

DETAILED DESCRIPTION

Referring to FIGS. 1, 2, and 3, a system 10 for use in a down hole wellbore application includes a housing 12, a valve 14 and a sleeve 16. Housing 12 at least partially encloses channel 13. Valve 14 includes a seat 18 and a flapper 22. Valve 14 may be positioned in region 20 of housing 12. In some embodiments, the valve seat may be formed as a single unitary body with the housing. Region 20 comprises a region having a greater interior diameter than adjacent regions. Flapper 22 may be generally curved so that when the valve is in the open position the cross-section of flapper 22 is curved and generally concentric with housing 12. Valve seat 18 may be generally cylindrical. Flapper 22 may be pivotally coupled to valve seat 18. By coupled, it is understood that flapper may be directly coupled to valve seat, or indirectly coupled by an intermediate member that is coupled to both the flapper and the valve seat (i.e., a flapper seat).

Sleeve 16 is positioned within valve 14 and prevents flapper 22 from closing against valve seat 18. Sleeve 16 may be specifically included as a component of system 10. An energy absorption device 24 is disposed between valve 14 and housing 12. In the case of a subsurface safety valve, upward pressure from wellbore fluids will cause valve 14 to close in the absence of sleeve 16. When valve 14 is closed, flapper 22 pivots about hinge 26 to mate with seat 18. The impact of flapper 22 on seat 18 may result in damage to the flapper, the seat, or other wellbore devices. Damage to valve 14's components may result in failure of valve 14 to retain wellbore fluids.

Housing 12 includes a projection 28 defining a shelf 30. Seat 18 includes an extension 32 that, with projection 28 partially defines region 34. In some embodiments, extension 32 may be sealingly and translatably coupled to projection 28. Energy absorption device 24 may be disposed within region 34. In the embodiment shown, energy absorption device 24 may comprise a first Belleville spring 36 and a second Belleville spring 38. Springs 36 and 38 are positioned such that springs 36 and 38 may be deflected when region 34 is compressed by lateral movement of the valve seat 18 with respect to housing 12. The deflection and subsequent return of springs 36 and 38 allows for the dissipation of impact energy from flapper 22 closing on seat 18. In alternative embodiments, a single Belleville spring may be used. In yet other embodiments, more than two Belleville springs may be used depending on the design needs for the wellbore.

Referring to FIG. 4, a system for use in a down hole wellbore application includes a housing 112, a valve 114 and a sleeve 116. Valve 114 includes a seat 118 and a flapper 122. Valve 114 may be positioned in region 120 of housing 112. Region 120 comprises a region having a greater interior diameter than adjacent regions. Flapper 122 may be generally curved so that when the valve is in the open position the cross section of flapper 122 is curved and generally concentric with housing 112. Flapper 122 may be hingedly coupled to the valve seat 118 through a hinge 126.

Housing 112 includes a projection 128 defining a shelf 130. Seat 118 includes an extension 132 that, with projection 128 partially defines region 134. In some embodiments, extension 132 may be sealingly and translatably coupled to projection 128. Energy absorption device 124 may be disposed within region 134. In the embodiment shown, energy absorption device 124 comprises a coil spring 140. Spring 140 is positioned such that springs 140 may be deflected when region 134 is compressed by lateral movement of the valve seat 118 with respect to housing 112. The deflection and subsequent return of spring 140 allows for the dissipation of impact energy from flapper 122 closing on seat 118. In alternative embodiments, other resilient devices including, but not limited to, multiple springs or types of springs may be used in combination.

Referring to FIG. 5, a system for use in a down hole wellbore application includes a housing 212, a valve 214 and a sleeve 216. Valve 214 includes a seat 218 and a flapper 222. Flapper 222 may be rotatively coupled to seat 218 via hinge 226. Valve 214 may be positioned in region 220 of housing 212. Region 220 comprises a region having a greater interior diameter than adjacent regions. Flapper 222 may be generally curved so that when the valve is in the open position the cross section of flapper 222 is curved and generally concentric with housing 212.

Housing 212 includes a projection 228 defining a shelf 230. Seat 218 includes an extension 232 that, with projection 228 partially defines region 234. In some embodiments, extension 232 may be sealingly and translatably coupled with projection 228. Energy absorption device 224 may be disposed within region 234. In the embodiment shown, energy absorption device 224 comprises a resilient ring 242 which may be composed of a polymer, such as an elastomeric or plastic material, among others. In other embodiments, a metal ring or other rigid material may be used such that the ring comprises a material having a low bulk modulus relative to the housing or the seat. Ring 242 is positioned such that ring 242 may be deflected and/or compressed when region 234 is compressed by lateral movement of the valve seat 218 with respect to housing 212. The deflection and subsequent return of spring 242 allows for the dissipation of impact energy from flapper 222 closing on seat 218. In alternative embodiments, multiple springs or types of springs may be used in combination.

Referring to FIG. 6, a valve 314 comprises a valve seat 318, a flapper seat 319, and a flapper 322. Flapper 322 is pivotally coupled to flapper seat 319 by a hinge 326. Flapper seat 319 is in turn coupled to valve seat 318. Valve 314 includes an energy absorption device 324. Energy absorption device 324 comprises a plunger 346 coupled to a spring 348 and is recessed into flapper seat 319, or, in other embodiments, valve seat 318. Plunger 346 extends beyond valve seat 318 and is configured to contact surface 350 of flapper 322 at a point prior to complete closure of valve 314. Spring 438 may be compressed and/or deflected to absorb the impact energy of flapper 322 as it closes on valve seat 318.

Although the foregoing has been described with reference to exemplary embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope thereof. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments.

The present subject matter described with reference to the example embodiments and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single particular element also encompass a plurality of such particular elements. In addition, for example, unless specifically otherwise noted, the claims reciting components coupled, mounted, or otherwise interacting together, may do so either directly or indirectly through one or more intermediate components.

Many other changes and modifications may be made to the present invention without departing from the spirit thereof. The scope of these and other changes will become apparent from the appended claims. The steps of the methods described herein may be varied, and carried out in different sequences. 

1. A system for use in a wellbore, comprising: a string comprising a housing in which the housing comprises a valve; wherein the valve comprises a valve seat and a flapper configured to pivot relative to the valve seat, the valve seat having an inner channel; wherein the flapper is configured to move between a first position and a second position in which the inner channel is obstructed in the second position; and an energy dampening device coupled to the valve seat; wherein the energy dampening device is configured to at least partially dissipate an impact of the flapper on the valve seat.
 2. The system of claim 1, further comprising a sleeve positioned in the inner channel of the valve seat and configured to retain the flapper in the first open position;
 3. The system of claim 1, wherein the energy dampening device is coupled to the valve seat at a position distal to the flapper.
 4. The system of claim 1, wherein the valve is a fluid loss control valve.
 5. The system of claim 1, wherein the energy dampening device comprises a spring.
 6. The system of claim 5, wherein the energy dampening device comprises at least one Belleville spring.
 7. The system of claim 6, wherein the energy dampening device comprises a plurality of Belleville springs.
 8. The system of claim 5, wherein the energy dampening device comprises a coiled spring.
 9. The system of claim 1, wherein the energy dampening device comprises a resilient ring.
 10. The system of claim 9, wherein the resilient ring comprises a polymer material.
 11. The system of claim 1, wherein the housing comprises an increased diameter portion for receiving the valve seat and the flapper.
 12. The system of claim 1, wherein the inner channel of the valve seat is substantially unobstructed by the flapper when the flapper is in the open position.
 13. A system for conveying wellbore fluids, comprising: a string having a housing, in which the housing comprises a safety valve; wherein the safety valve comprises a valve seat and a flapper configured to pivot relative to the valve seat, the valve seat having an inner channel; wherein the flapper is configured to move between a first position and a second position in which the inner channel is obstructed in the second position; and an energy dampening device configured to oppose at least a portion of a motion of the flapper moving to the second position; wherein the energy dampening device is configured to at least partially reduce an impact of the flapper on the valve seat.
 14. The system of claim 13, wherein the energy dampening device comprises a spring.
 15. The system of claim 14, wherein the energy dampening device comprises a plurality of Belleville springs.
 16. The system of claim 14, wherein the energy dampening device comprises a coiled spring.
 17. A valve for use in a wellbore comprising: a valve seat, the valve seat having an inner channel; a flapper pivotally coupled to the valve seat, the flapper configured to move between a first position and a second position in which the inner channel is obstructed; and a sleeve positioned in the inner channel of the valve seat and configured to retain the flapper in the first position; an energy dampening device coupled to the valve seat; wherein the energy dampening device is configured to at least partially absorb an impact of the flapper on the valve seat.
 18. The system of claim 14, wherein the energy dampening device is coupled to the valve seat at a position distal to the flapper.
 19. The system of claim 17, wherein the energy dampening device is coupled to the valve seat at a position proximate to the flapper.
 20. The system of claim 19, wherein the energy dampening device comprises a plunger and a spring, the plunger having a surface configured to engage the flapper. 